Avoid excess processing overhead when/if  incr == 1 in BH .sdt files.
Ensure that Load_IRF_annot still recognises .sdt files even if the name is modified on import to OMERO (see https://github.com/openmicroscopy/Imperial-FLIMfit/issues/76)
Change strfind for findstr in previous commit + a little tidying up.
Hopefully got the right one (strfind) this time.